tress       
noun [ C ]  literary uk/tres/ us/tres/
 一缕长发
a section or curl of someone's long hair
  He lay with his head against the maiden's heart, bound close to her by a tress of her long hair. 他头靠着少女的心脏躺着,紧紧裹在她的一缕长发中。 
 See also: tresses
 - More examples
 - She spoke in a dreamy way as she wound the long tress of hair tight round and round her hand.
 - Lucenzo reached out and pushed back the tress of copper hair which had fallen over her forehead.
 - Just as he took the tress firmly in his left hand, and was about to attack it also with the clippers, he spotted a reflection in the surrounding mirrors.